Explanation:
These three bright nebulae are often
featured in telescopic tours of the constellation
Sagittarius and the crowded starfields of
the central Milky Way.
In fact, 18th century cosmic tourist
Charles Messier
cataloged two of them; M8, the nebula below and right of center,
and colorful M20 at the upper right.
The third, NGC 6559, is left of M8,
separated from the the larger nebula by a dark dust lane.
All three are stellar nurseries about
five thousand light-years or so distant.
The expansive M8, over a hundred light-years across,
is also known as the Lagoon Nebula while M20's popular moniker is
the Trifid.
This stunning digital view is actually a collaborative
composite recorded by 2 cameras and 2 telescopes
about 2 thousand miles apart.
The deep, wide image field was captured under dark
Arizona
skies.
Both M8 and M20 were recorded in more detail from
an
observatory in Pennsylvania.
Glowing hydrogen gas creates the dominant red color of the
emission nebulae, with contrasting blue hues, most striking in the
Trifid, due to dust reflected starlight.